1. Field of the Invention
The present invention relates to combine skid plates or shoes for agricultural equipment. More specifically, the invention relates to a protective cover for such skid plates or shoes for preventing adhesion of soil thereto and the damage caused adhesion of the soil to the skid plates and the combine header.
2. Related Art
My U.S. Pat. No. 4,729,212, which is incorporated herein by reference in its entirety, is directed to a protective cover for skid plates of a self-propelled combine 10 as shown in FIG. 1. This protective cover comprises a plurality of side-by-side cover panels, each cover panel corresponding to a specific skid plate panel of the combine, and the inner surface of each cover panel being configured to matingly engage the outer surface of its corresponding skid plate panel. The cover panels are attached to their corresponding skid plate panels by rivets, bolts, screws, or the like fasteners inserted through pre-drilled holes in the cover panels and corresponding holes either pre-punched by the manufacturer or drilled by the installer in the skid plate panels. The cover panels are made from a plastic material, preferably an ultra high molecular weight polyethylene plastic, having a low coefficient of friction to resist the adhesion of soil thereto.
Due to the success of the invention which is the subject of my '212 patent, at least one major manufacturer of combines has begun to pre-punch holes in their combine skid plate panels at the time of manufacture, in order to enable installation of the cover panels in accordance with the '212 patent at the factory or as a dealer-installed option. However, the manufacturing tolerance both in the pre-punched holes and in the angle of the outer surface of the combine skid plate panels is substantial, sometimes resulting in a lack of the necessary mating engagement between the combine skid plate panels and their cover panels. Further adding to this problem is the fact that the passage of time and variations in temperature may result in deformation of the cover panels. In particular, the cover panels are bent into their required configurations by cold pressing, and the plastic material used for the cover panels "remembers" its original shape, so that over time, the cover panels tend to flatten out. Also, the plastic material may expand or contract due to temperature variations. It is to the solution of these and other problems to which the present invention is directed.